Project Summary/Abstract Postpartum depressive (PPD) symptoms are common among women following the birth of a child and can adversely impact a mother's ability to care for her child. As a result, infants of mothers with PPD symptoms may experience less responsive parenting, placing them at greater risk for delays in development. Evidence- based parenting programs have been developed to guide mothers with caring for their infants but may not address the impact of depression on parenting, are intensive and expensive to administer with limited ability for scale up, or are not available in a format that facilitates participation by women with depressive symptoms. Therefore, these women may not be able to take advantage of the benefits of parenting programs. Our long- term goal is to develop effective parenting strategies to facilitate optimal child development for mothers suffering with PPD symptoms. Our overall objective for this application is to study whether this program combined with online depression treatment leads to more responsive parenting (target) and signals improved child language, socioemotional and cognitive development (outcomes) compared to depression treatment alone. The specific aims are 1) to determine whether a social media-based parenting program can improve responsive parenting (target) among mothers with PPD symptoms, 2) to determine whether a social media- based parenting program can improve responsive parenting (target) and signal greater child development (outcome) among mothers with PPD symptoms, and 3) to explore mediators and moderators of the effects of the parenting program on responsive parenting. The proposed study will occur at 3-4 primary care practices affiliated with a large urban children's hospital and consist of 2 phases: an initial pilot RCT testing engagement of the parenting program on responsive parenting (R61) and a subsequent RCT further testing engagement of the program and exploring child development and mediators and moderators of treatment effect (R33). In the first phase, 75 ethnically and racially diverse women who screen positive for PPD symptoms and have infants <6 months of age will be randomized to receive the parenting program plus online depression treatment or online depression treatment alone to assess target engagement. In the second phase, an additional 75 eligible women will be randomized to receive the parenting program plus online depression treatment or depression treatment alone. In this latter phase, we will further determine whether the parenting program effectively engages the proposed target, responsive parenting, and signals greater child developmental status than the online depression treatment program. In addition, we will explore mediators and moderators of treatment effects on responsive parenting. The results of this application would be expected to contribute important new knowledge and inform a future trial on parenting strategies to better assist mothers with PPD symptoms and improve child developmental outcomes.